A common air-conditioning apparatus is equipped with an outdoor unit having a compressor, a four-way valve serving as flow switching means for switching the flowing direction of a refrigerant, an outdoor heat exchanger and a pressure-reducing capillary tube connected to an outlet of the outdoor heat exchanger, and an electronic expansion valve that further reduces the pressure of the refrigerant after having passed through the capillary tube; and an indoor unit having an indoor heat exchanger. The aforementioned devices contained in the outdoor unit and the indoor unit are sequentially connected by refrigerant pipes in the form of a circuit, and the refrigerant circulates through the refrigerant circuit, whereby a refrigeration cycle is formed. When the indoor heat exchanger operates as an evaporator and the outdoor heat exchanger operates as a condenser, indoor cooling is achieved. On the other hand, when the indoor heat exchanger operates as a condenser and the outdoor heat exchanger operates as an evaporator, indoor heating is achieved. The four-way valve provided at the discharge side of the compressor switches the flowing direction of the refrigerant so that the refrigerant discharged from the compressor is condensed by the indoor heat exchanger or the outdoor heat exchanger. Fans are disposed near the indoor heat exchanger and the outdoor heat exchanger and send indoor air and outdoor air thereto, respectively.
In recent years, outdoor units that can be used in various ways and can be connected to various types of indoor units in accordance with users' demands are in demand. In this case, since the capacity of and the amount of air for the indoor heat exchanger vary depending on the type of indoor unit, the amount of refrigerant for allowing the refrigeration cycle to exhibit maximum performance would also vary. In order to properly adjust the amount of refrigerant circulating through the refrigerant circuit, an excess-refrigerant container is provided in the refrigerant circuit for retaining an excess refrigerant. A receiver serving as this excess-refrigerant container is often disposed in a suction pipe of the compressor or at a position where a liquid refrigerant exists, such as a position between an outlet of the condenser and an inlet of the evaporator.
In the air-conditioning apparatus having such a configuration, if a large amount of refrigerant that covers the entire refrigerant circuit is to be injected into the refrigerant circuit during production or maintenance of the air-conditioning apparatus, the refrigerant is injected from a refrigerant injection port provided in the refrigerant circuit. In particular, a configuration is disclosed in which the refrigerant is injected into the refrigerant circuit from a refrigerant injection port provided in the suction pipe of the compressor, an inlet pipe of a heat exchanger, or an outlet pipe of the heat exchanger (e.g., see Patent Literature 1).